[HouHaunter]

I know I don't post here much, but us old Haunters will still ask for help when needed. I want to have a prop (don't know what it would be yet) go around a corner. I cannot drop from ceiling because of garage door. But can I have something lunge around a corner? Are there any tutorials discussing this? I am windshield wiper motor and air pneumatic and mechanically savvy. But how do I lunge and turn 180 degrees? I can't afford to purchase from the great manufacturers we home haunters have supported. Any help would be much appreciated!

 

[ghostlland820]

Without knowing what your envisioning: Maybe something on a large turntable of some sort? But I don't know that you could make it fast enough for a "lunge."

 

[HouHaunter]

Electrocution Chamber. Victims face forward. something lunges forward then turns 45/180 degrees? right in front of victims. I think its

what i'm trying to achieve,

 

[wdallen504]

I would think a spring loaded armature that is retracted by a wiper motor would do the trick. Using an electromagnetic clutch system for the release (scare) sequence. They can be found for less than $100. The octobanger prop controller ( or similar) can run the entire sequence.

Electromagnetic clutch

 

[Bonescraper]

Maybe a track and then a secondaryw, scissor mech

 

[wdallen504]

Another way is with the screen door cylinder. There are a lot of DIY videos on how to convert them for compressed air. Their range of motion is quite big and they are really powerful. I used them in my pirate cannon build. Their built in spring retracts the prop very nicely.

 

[Mapleton Manor]

If you build a simple pnuematic ran turntable so that it will rotate the 180 degrees around the corner. Then build a simple scissor mechanism that runs off a stop so that when it is half way around the corner it starts to jump out. And then have a spring on it that retracts when it goes back around the corner. Simple mechanics. I have a coffin that has a guy that raises in it and when he gets up about half way he turns just from a stop built in that turns him. Done with one pnuematic cylinder. Wont have it out for a few months or I would show it to you.

 

[Mapleton Manor]

 

[ghostlland820]

I just saw this today. Smaller than what you need, but you might get some ideas from the mechanics.

Swiping Through Wall Mech (Pneumatic)

 

[Skeleton_Dave]

I know I don't post here much, but us old Haunters will still ask for help when needed. I want to have a prop (don't know what it would be yet) go around a corner. I cannot drop from ceiling because of garage door. But can I have something lunge around a corner? Are there any tutorials discussing this? I am windshield wiper motor and air pneumatic and mechanically savvy. But how do I lunge and turn 180 degrees? I can't afford to purchase from the great manufacturers we home haunters have supported. Any help would be much appreciated!

This was just released today. Maybe it might help you

Swiping Through Wall Mech (Pneumatic)

Mech designed to swing through a hole in a wall and then grab. Add a hand and sleeve to make it look like a zombie or monster is grabbing through the wall!

www.frightprops.com

 

[Skeleton_Dave]

I know I don't post here much, but us old Haunters will still ask for help when needed. I want to have a prop (don't know what it would be yet) go around a corner. I cannot drop from ceiling because of garage door. But can I have something lunge around a corner? Are there any tutorials discussing this? I am windshield wiper motor and air pneumatic and mechanically savvy. But how do I lunge and turn 180 degrees? I can't afford to purchase from the great manufacturers we home haunters have supported. Any help would be much appreciated!

This was just released, maybe it can help you.

Swiping Through Wall Mech (Pneumatic)

Mech designed to swing through a hole in a wall and then grab. Add a hand and sleeve to make it look like a zombie or monster is grabbing through the wall!

www.frightprops.com

 

[sbbbugsy0473]

You could mount a 90 degree arm on a spinning axis to keep it simple.

 

[wdallen504]

I just saw this today. Smaller than what you need, but you might get some ideas from the mechanics.

Swiping Through Wall Mech (Pneumatic)

That is a great mech!

 

[Mapleton Manor]

My thought is to take ssbugsys idea of the pivot and on the outside set up a scissor mechanism with a stop that once it is halfway around the corner it engages the scissor and allows it to extend. The stop would need to be angled in two directions both out and forward so that as the prop continues to move around the corner it extends the scissor freely. A spring on the scissor would allow it to retract as it returns to its home position. I know my drawings arent the best but something like this is what is in my head.

 

[Oak Lane Cemetery]

Hinge it to the wall and push it with a pneumatic or motor. Think of it as a door instead of a prop.

 

[cadcoke5]

Some of the suggestions involved what is called a four bar linkage. There are some online simulators you can use to test various lengths for the linkage bars. That way you can get a feel for how they work. I think you would want to use the approach where the linkages form an x.

But actually I think a system where you have a mechanism that extends. Then towards the end of travel, a cord reaches the end of it's travel, and causes a bar at the end to pivot

 

[A Guy In Town]

You would cut a telescoping pipe at an angle, and raise and drop it as needed. This is how swinging doors work.

GREASE the sliding, rotating segment well, and make sure little fingers CANNOT get to the PINCH ZONE!

This can be done with metal pipe or thick wall (SCH 80) ABS pipe.

The speed of the motion is determined by the weight of the door (prop) and the angle of the outer pipe. Raise the prop and it rotates 180 counter-clockwise. DROP the prop and it quickly rotates clockwise.

Joe

 

[cadcoke5]

But actually I think a system where you have a mechanism that extends.... Then towards the end of travel, a cord reaches the end of it's travel, and causes a bar at the end to pivot

I now see that I didn't explain that well. Perhaps an illustration would be better anyway. The part that pivots is on the end of a linear actuator. (though it could also be some sort of swinging arm instead of the linear actuator). Towards the end of travel, a cord or chain becomes tight, and causes the pivoting object to be pulled and turned. When the linear actuator retracts, a spring pulls it back.

 

[A Guy In Town]

I now see that I didn't explain that well. Perhaps an illustration would be better anyway. The part that pivots is on the end of a linear actuator. (though it could also be some sort of swinging arm instead of the linear actuator). Towards the end of travel, a cord or chain becomes tight, and causes the pivoting object to be pulled and turned. When the linear actuator retracts, a spring pulls it back.
View attachment 775321

How would that achieve 180 degrees of rotation?

Joe

 

[cadcoke5]

How would that achieve 180 degrees of rotation?

The drawing is just a conceptional one, so the location and length of the crank arm, as well as the spring, need to be adjusted. The length of the lunge is an important factor that affect the crank arm length and position. Specifically, the length of the lunge must be equal to the chord of the arc that the crank arm travels. And if the crank arm part is shorter, then the rotating part will need a shorter length of the linear actuator's travel to cause the turn. Unless you are comfortable with the math involved, it is probably easier to just make a test model using cardboard or perhaps foam (or alternatively a CAD system). Then play with some of the geometries.

Also, the mechanism I drew would realistically only achieve 170 deg, not a full 180. If you really want the 180 deg, you might consider adding a motor at the end of the linear actuator. Though, that is more expense, and you either have to trigger the rotation motor separately, or perhaps if the rotation motor is slower than the linear actuator, you can trigger both at the same time.

Below is the same mechanism i drew, but I just positioned its starting point differently.

-Joe